help please- spray foam closed cell insulation disaster

A homeowner on the South Shore of Massachusetts is dealing with a spray foam insulation job gone wrong. Closed-cell spray foam (a dense, plastic-like foam insulation sprayed into attics and walls) was installed in their attic, and more than 35 days later it's still releasing a strong chemical smell. The installer tried blaming a separate fireproof coating, removed and replaced it, but the odor persisted. The family has been out of their house for over a month, through a range of fall temperatures, and say air quality tests show pollutant levels in a "moderate but elevated" range. They're now asking the installer to remove the foam entirely.

Responses from building science forum members offered a blunt diagnosis: a bad chemical mix during spraying can leave foam that never fully cures, meaning it keeps off-gassing indefinitely. In cases like this, patching or adding more product rarely fixes the problem — full removal and specialized cleaning is usually the only real option. One commenter also noted that homeowners in this situation sometimes need to pursue legal action to get the cost of removal and cleanup covered.

For homeowners considering spray foam insulation, the case is a reminder that improper mixing or application during installation can turn into a serious, long-lasting indoor air quality problem rather than a quick fix. If you ever notice a chemical smell lingering well beyond the first few days after a spray foam job, it's worth treating that as a sign something went wrong with the installation itself.